3 monitors, solutions? recommendations?

Ive looked around a bit and i need the hard facts before spending a lot of money on hardware that might not work for what i want. i know ive found partial answers all over and im getting confused. my questions are, i have 3 monitors and i want to play games with them. I got a 9800gtx on a asus commando board (little old now but meh it works) so Matrox triplehead2go digital version, something like $350 ($410cdn). to my knowledge of this product is that i can run one graphic card dvi connector and it will run 3 monitors in games and mak them act as one but the graphic card has to run 3 monitors and brings the performance down. so i can get another card, not sure if the 9800gt is compatible with a 9800gtx 512mb card so thats another question for you guys.

what are the other solutions? big bang drivers from nvidia and get triple sli to run 3-4 screens? thats buying 2 extra cards and a new mobo. anything buying another graphic card is a new mobo because the commando is a 16x, 4x pcie slots. not a dual full 16x. and its not a pcie2 board. not sure what to do..

some recommendations, suggestions, opinions are welcome and ill keep checking back. thanks.

but would that work running a game on all 3 screens? like a 3 screen span? at 1680x1050 x3 or its 5040x1050 if your looking at it as one screen. im currently running vista and read something about it not being able to do horizontal spanning, i have a copy of xp as well so i can install that.